#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>

int g_val = 100;

int main()
{
	pid_t id = fork();
		//子进程
		int cnt = 5;
		while(1)
		{
			printf("I am a child, pid = %d, ppid = %d, g_val = %d, &g_val = %p\n", getpid(), getppid(), g_val, &g_val);
			sleep(1);
			if(cnt) cnt--;
			else
			{
				g_val = 200;
				printf("子进程 change g_val:100 -> 200\n");
				cnt--;
			}
		}
	}
	else
	{
		//父进程
		while(1)
		{
			printf("I am a father, pid = %d, ppid = %d, g_val = %d, &g_val = %p\n", getpid(), getppid(), g_val, &g_val);
			sleep(1);
		}
		
	}
	return 0;
}



